# How to verify if your Supabase is publicly writable (safely)

A safe approach to checking whether public INSERT is possible without leaving meaningful data behind.

“Is this table writable from the public internet?” is a high-impact question. The tricky part is verifying it without accidentally inserting real data.

## Use a minimal insert probe

When possible, send an INSERT with minimal payload and request minimal return data. If the backend supports transaction rollback (or you can write into a disposable table), you can confirm writability without lasting changes.

## Treat write access as urgent

Public write access can enable spam, data corruption, or privilege escalation depending on what the table controls. Fixes typically involve enabling RLS and tightening INSERT/UPDATE policies.

Supaguard’s scanner uses a “single insert probe” approach designed to confirm permissions without meaningful writes.